| Message ID | 20230314182405.2449898-3-vladimir.oltean@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7e9517375a14f44ee830ca1c3278076dd65fcc8f |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Fix MTU reporting for Marvell DSA switches where we can't change it | expand |
| Context | Check | Description |
|---|---|---|
| netdev/series_format | success | Posting correctly formatted |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/fixes_present | success | Fixes tag present in non-next series |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 18 this patch: 18 |
| netdev/cc_maintainers | success | CCed 8 of 8 maintainers |
| netdev/build_clang | success | Errors and warnings before: 18 this patch: 18 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/deprecated_api | success | None detected |
| netdev/check_selftest | success | No net selftest shell script |
| netdev/verify_fixes | success | Fixes tag looks correct |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 18 this patch: 18 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 34 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
On Tue, Mar 14, 2023 at 08:24:05PM +0200, Vladimir Oltean wrote: > There are 3 classes of switch families that the driver is aware of, as > far as mv88e6xxx_change_mtu() is concerned: > > - MTU configuration is available per port. Here, the > chip->info->ops->port_set_jumbo_size() method will be present. > > - MTU configuration is global to the switch. Here, the > chip->info->ops->set_max_frame_size() method will be present. > > - We don't know how to change the MTU. Here, none of the above methods > will be present. > > Switch families MV88E6165, MV88E6191, MV88E6220, MV88E6250 and MV88E6290 > fall in category 3. > > The blamed commit has adjusted the MTU for all 3 categories by EDSA_HLEN > (8 bytes), resulting in a new maximum MTU of 1492 being reported by the > driver for these switches. > > I don't have the hardware to test, but I do have a MV88E6390 switch on > which I can simulate this by commenting out its .port_set_jumbo_size > definition from mv88e6390_ops. The result is this set of messages at > probe time: > > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 1 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 2 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 3 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 4 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 5 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 6 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 7 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 8 > > It is highly implausible that there exist Ethernet switches which don't > support the standard MTU of 1500 octets, and this is what the DSA > framework says as well - the error comes from dsa_slave_create() -> > dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN). > > But the error messages are alarming, and it would be good to suppress > them. > > As a consequence of this unlikeliness, we reimplement mv88e6xxx_get_max_mtu() > and mv88e6xxx_change_mtu() on switches from the 3rd category as follows: > the maximum supported MTU is 1500, and any request to set the MTU to a > value larger than that fails in dev_validate_mtu(). > > Fixes: b9c587fed61c ("dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports") > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Simon Horman <simon.horman@corigine.com>
On 3/14/23 11:24, Vladimir Oltean wrote: > There are 3 classes of switch families that the driver is aware of, as > far as mv88e6xxx_change_mtu() is concerned: > > - MTU configuration is available per port. Here, the > chip->info->ops->port_set_jumbo_size() method will be present. > > - MTU configuration is global to the switch. Here, the > chip->info->ops->set_max_frame_size() method will be present. > > - We don't know how to change the MTU. Here, none of the above methods > will be present. > > Switch families MV88E6165, MV88E6191, MV88E6220, MV88E6250 and MV88E6290 > fall in category 3. > > The blamed commit has adjusted the MTU for all 3 categories by EDSA_HLEN > (8 bytes), resulting in a new maximum MTU of 1492 being reported by the > driver for these switches. > > I don't have the hardware to test, but I do have a MV88E6390 switch on > which I can simulate this by commenting out its .port_set_jumbo_size > definition from mv88e6390_ops. The result is this set of messages at > probe time: > > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 1 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 2 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 3 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 4 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 5 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 6 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 7 > mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 8 > > It is highly implausible that there exist Ethernet switches which don't > support the standard MTU of 1500 octets, and this is what the DSA > framework says as well - the error comes from dsa_slave_create() -> > dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN). > > But the error messages are alarming, and it would be good to suppress > them. > > As a consequence of this unlikeliness, we reimplement mv88e6xxx_get_max_mtu() > and mv88e6xxx_change_mtu() on switches from the 3rd category as follows: > the maximum supported MTU is 1500, and any request to set the MTU to a > value larger than that fails in dev_validate_mtu(). > > Fixes: b9c587fed61c ("dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports") > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 0a5d6c7bb128..30383c4f8fd0 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -3549,7 +3549,7 @@ static int mv88e6xxx_get_max_mtu(struct dsa_switch *ds, int port) return 10240 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; else if (chip->info->ops->set_max_frame_size) return 1632 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; - return 1522 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; + return ETH_DATA_LEN; } static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) @@ -3557,6 +3557,17 @@ static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) struct mv88e6xxx_chip *chip = ds->priv; int ret = 0; + /* For families where we don't know how to alter the MTU, + * just accept any value up to ETH_DATA_LEN + */ + if (!chip->info->ops->port_set_jumbo_size && + !chip->info->ops->set_max_frame_size) { + if (new_mtu > ETH_DATA_LEN) + return -EINVAL; + + return 0; + } + if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port)) new_mtu += EDSA_HLEN; @@ -3565,9 +3576,6 @@ static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) ret = chip->info->ops->port_set_jumbo_size(chip, port, new_mtu); else if (chip->info->ops->set_max_frame_size) ret = chip->info->ops->set_max_frame_size(chip, new_mtu); - else - if (new_mtu > 1522) - ret = -EINVAL; mv88e6xxx_reg_unlock(chip); return ret;
There are 3 classes of switch families that the driver is aware of, as far as mv88e6xxx_change_mtu() is concerned: - MTU configuration is available per port. Here, the chip->info->ops->port_set_jumbo_size() method will be present. - MTU configuration is global to the switch. Here, the chip->info->ops->set_max_frame_size() method will be present. - We don't know how to change the MTU. Here, none of the above methods will be present. Switch families MV88E6165, MV88E6191, MV88E6220, MV88E6250 and MV88E6290 fall in category 3. The blamed commit has adjusted the MTU for all 3 categories by EDSA_HLEN (8 bytes), resulting in a new maximum MTU of 1492 being reported by the driver for these switches. I don't have the hardware to test, but I do have a MV88E6390 switch on which I can simulate this by commenting out its .port_set_jumbo_size definition from mv88e6390_ops. The result is this set of messages at probe time: mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 1 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 2 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 3 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 4 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 5 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 6 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 7 mv88e6085 d0032004.mdio-mii:10: nonfatal error -34 setting MTU to 1500 on port 8 It is highly implausible that there exist Ethernet switches which don't support the standard MTU of 1500 octets, and this is what the DSA framework says as well - the error comes from dsa_slave_create() -> dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN). But the error messages are alarming, and it would be good to suppress them. As a consequence of this unlikeliness, we reimplement mv88e6xxx_get_max_mtu() and mv88e6xxx_change_mtu() on switches from the 3rd category as follows: the maximum supported MTU is 1500, and any request to set the MTU to a value larger than that fails in dev_validate_mtu(). Fixes: b9c587fed61c ("dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- drivers/net/dsa/mv88e6xxx/chip.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)